Halo 3 Marine-Ellis (Mod) for Left 4 Dead 2

Steam Workshop::Survivors - Ellis

NPCs, Left 4 Dead Wiki

L4D2] Halo Spartans [Left 4 Dead 2] [Mods]

If there's no ODST-Flood horror game, then I'll make one myself [L4D2] : r/ halo

Images at Left 4 Dead 2 - Mods and community

Halo 2 Anniversary: UNSC Marines Cosmetics - Skymods

Steam Workshop::L4D2 Collection [#2]

Steam Workshop::Halo 3 Type-3 Antipersonnel Incendiary grenade (Molotov)

Download 'halo' Mods for Left 4 Dead 2